The preoperative levels of serum-soluble receptor for interleukin-2 (IL-2R) were determined by an enzyme-linked immunosorbent assay in 38 patients undergoing surgery for colorectal cancer and 98 healthy controls. The levels of serum-soluble IL-2R in the patients with colorectal cancer were significantly higher than those in the normal controls (P<0.05). Markedly elevated levels of serum-soluble IL-2R were recognized in patients with stage IV cancer, those with Dukes' stage D cancer, and those with liver metastasis. Moreover, the prognosis of patients with low levels of IL-2R (<531 U/ml) was significantly better than that of those with high levels (P<0.05). These findings demonstrate that an elevated concentration of soluble IL-2R might be a useful indicator of liver metastasis and poor prognosis in patients with colorectal carcinoma.